An FIB-SEM system is equipped with a focused ion beam (FIB) capable of performing nano-level processing and a scanning electron microscope (SEM) capable of performing nano-level observation, and is used in various fields such as semiconductor, materials, and biotechnology fields. The most striking feature of the FIB-SEM system is that a cross section processed by the FIB can be observed by the SEM on the spot. This allows the FIB processing to be controlled with high precision. When performing a failure analysis on a semiconductor device, for example, the FIB processing can be easily stopped at a specific cross section.
Japanese Patent Application No. 2005-108545 (PTL 1) discloses that a photoelectron microscope combining an electron microscope and an X-ray photoelectron spectroscopy, which acquires a photoelectron with specific energy and acquires information on a bonding state, or a secondary ion/electron microscope using an excited secondary ion as a source of image encoding eliminates a spherical aberration by a method of using a color aberration in an image forming optical system by wavelength modulation of radiated light and changing (modulating) a focus position of the system at high speed, a method of changing (modulating) a lens system at high speed, and a method of changing (modulating) a sample position at high speed.
Moreover, Japanese Patent Application No. 58-158848 (PTL 2) discloses an electron detector capable of detecting a secondary electron and a reflected electron simultaneously by including a light guide, two layers of scintillators formed on an electron incident surface of the light guide and formed of materials having different emission spectra, spectroscopic means installed on the emission side of the light guide to separate light from each scintillator, and photoelectricity detection means that detects each light being separated.
Moreover, Japanese Patent Application No. 9-161712 (PTL 3) discloses an observation apparatus that processes a sample with an ion beam, the apparatus including means that selects and detects a reflected electron acquired by irradiating the sample with an electron beam. It is described in PTL 3 that while a secondary electron generated by the ion beam irradiation cannot be distinguished from a secondary electron generated by the electron beam irradiation, the reflected electron returning by the action of elastic scattering of the electron beam has higher energy than the secondary electron and can thus be distinguished from the secondary electron in terms of the energy difference, whereby one can observe how the sample changes in shape without suspending the ion beam processing in the middle thereof.